# #########################     LICENSE     ############################ #
# flake8: noqa
# type: ignore

# Copyright (c) 2005-2016, Michele Simionato
# All rights reserved.

# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:

#   Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
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#   notice, this list of conditions and the following disclaimer in
#   the documentation and/or other materials provided with the
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
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# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
# DAMAGE.

"""
Decorator module, see http://pypi.python.org/pypi/decorator
for the documentation.
"""
from __future__ import print_function

import collections
import inspect
import itertools
import operator
import re
import sys

__version__ = "4.0.10"

if sys.version >= "3":
    from inspect import getfullargspec  # type: ignore

    def get_init(cls):
        return cls.__init__


else:

    class getfullargspec(object):  # type: ignore
        "A quick and dirty replacement for getfullargspec for Python 2.X"

        def __init__(self, f):
            self.args, self.varargs, self.varkw, self.defaults = inspect.getargspec(f)
            self.kwonlyargs = []
            self.kwonlydefaults = None

        def __iter__(self):
            yield self.args
            yield self.varargs
            yield self.varkw
            yield self.defaults

        getargspec = inspect.getargspec

    def get_init(cls):
        return cls.__init__.__func__


# getargspec has been deprecated in Python 3.5
ArgSpec = collections.namedtuple("ArgSpec", "args varargs varkw defaults")


def getargspec(f):
    """A replacement for inspect.getargspec"""
    spec = getfullargspec(f)
    return ArgSpec(spec.args, spec.varargs, spec.varkw, spec.defaults)


DEF = re.compile("\s*def\s*([_\w][_\w\d]*)\s*\(")


# basic functionality
class FunctionMaker(object):
    """
    An object with the ability to create functions with a given signature.
    It has attributes name, doc, module, signature, defaults, dict and
    methods update and make.
    """

    # Atomic get-and-increment provided by the GIL
    _compile_count = itertools.count()

    def __init__(self, func=None, name=None, signature=None, defaults=None, doc=None, module=None, funcdict=None):
        self.shortsignature = signature
        if func:
            # func can be a class or a callable, but not an instance method
            self.name = func.__name__
            if self.name == "<lambda>":  # small hack for lambda functions
                self.name = "_lambda_"
            self.doc = func.__doc__
            self.module = func.__module__
            if inspect.isfunction(func):
                argspec = getfullargspec(func)
                self.annotations = getattr(func, "__annotations__", {})
                for a in ("args", "varargs", "varkw", "defaults", "kwonlyargs", "kwonlydefaults"):
                    setattr(self, a, getattr(argspec, a))
                for i, arg in enumerate(self.args):
                    setattr(self, "arg%d" % i, arg)
                if sys.version < "3":  # easy way
                    self.shortsignature = self.signature = inspect.formatargspec(formatvalue=lambda val: "", *argspec)[
                        1:-1
                    ]
                else:  # Python 3 way
                    allargs = list(self.args)
                    allshortargs = list(self.args)
                    if self.varargs:
                        allargs.append("*" + self.varargs)
                        allshortargs.append("*" + self.varargs)
                    elif self.kwonlyargs:
                        allargs.append("*")  # single star syntax
                    for a in self.kwonlyargs:
                        allargs.append("%s=None" % a)
                        allshortargs.append("%s=%s" % (a, a))
                    if self.varkw:
                        allargs.append("**" + self.varkw)
                        allshortargs.append("**" + self.varkw)
                    self.signature = ", ".join(allargs)
                    self.shortsignature = ", ".join(allshortargs)
                self.dict = func.__dict__.copy()
        # func=None happens when decorating a caller
        if name:
            self.name = name
        if signature is not None:
            self.signature = signature
        if defaults:
            self.defaults = defaults
        if doc:
            self.doc = doc
        if module:
            self.module = module
        if funcdict:
            self.dict = funcdict
        # check existence required attributes
        assert hasattr(self, "name")
        if not hasattr(self, "signature"):
            raise TypeError("You are decorating a non function: %s" % func)

    def update(self, func, **kw):
        "Update the signature of func with the data in self"
        func.__name__ = self.name
        func.__doc__ = getattr(self, "doc", None)
        func.__dict__ = getattr(self, "dict", {})
        func.__defaults__ = getattr(self, "defaults", ())
        func.__kwdefaults__ = getattr(self, "kwonlydefaults", None)
        func.__annotations__ = getattr(self, "annotations", None)
        try:
            frame = sys._getframe(3)
        except AttributeError:  # for IronPython and similar implementations
            callermodule = "?"
        else:
            callermodule = frame.f_globals.get("__name__", "?")
        func.__module__ = getattr(self, "module", callermodule)
        func.__dict__.update(kw)

    def make(self, src_templ, evaldict=None, addsource=False, **attrs):
        "Make a new function from a given template and update the signature"
        src = src_templ % vars(self)  # expand name and signature
        evaldict = evaldict or {}
        mo = DEF.match(src)
        if mo is None:
            raise SyntaxError("not a valid function template\n%s" % src)
        name = mo.group(1)  # extract the function name
        names = set([name] + [arg.strip(" *") for arg in self.shortsignature.split(",")])
        for n in names:
            if n in ("_func_", "_call_"):
                raise NameError("%s is overridden in\n%s" % (n, src))

        if not src.endswith("\n"):  # add a newline for old Pythons
            src += "\n"

        # Ensure each generated function has a unique filename for profilers
        # (such as cProfile) that depend on the tuple of (<filename>,
        # <definition line>, <function name>) being unique.
        filename = "<decorator-gen-%d>" % (next(self._compile_count),)
        try:
            code = compile(src, filename, "single")
            exec(code, evaldict)
        except:
            print("Error in generated code:", file=sys.stderr)
            print(src, file=sys.stderr)
            raise
        func = evaldict[name]
        if addsource:
            attrs["__source__"] = src
        self.update(func, **attrs)
        return func

    @classmethod
    def create(cls, obj, body, evaldict, defaults=None, doc=None, module=None, addsource=True, **attrs):
        """
        Create a function from the strings name, signature and body.
        evaldict is the evaluation dictionary. If addsource is true an
        attribute __source__ is added to the result. The attributes attrs
        are added, if any.
        """
        if isinstance(obj, str):  # "name(signature)"
            name, rest = obj.strip().split("(", 1)
            signature = rest[:-1]  # strip a right parens
            func = None
        else:  # a function
            name = None
            signature = None
            func = obj
        self = cls(func, name, signature, defaults, doc, module)
        ibody = "\n".join("    " + line for line in body.splitlines())
        return self.make("def %(name)s(%(signature)s):\n" + ibody, evaldict, addsource, **attrs)


def decorate(func, caller):
    """
    decorate(func, caller) decorates a function using a caller.
    """
    evaldict = dict(_call_=caller, _func_=func)
    fun = FunctionMaker.create(func, "return _call_(_func_, %(shortsignature)s)", evaldict, __wrapped__=func)
    if hasattr(func, "__qualname__"):
        fun.__qualname__ = func.__qualname__
    return fun


def decorator(caller, _func=None):
    """decorator(caller) converts a caller function into a decorator"""
    if _func is not None:  # return a decorated function
        # this is obsolete behavior; you should use decorate instead
        return decorate(_func, caller)
    # else return a decorator function
    if inspect.isclass(caller):
        name = caller.__name__.lower()
        doc = "decorator(%s) converts functions/generators into " "factories of %s objects" % (
            caller.__name__,
            caller.__name__,
        )
    elif inspect.isfunction(caller):
        if caller.__name__ == "<lambda>":
            name = "_lambda_"
        else:
            name = caller.__name__
        doc = caller.__doc__
    else:  # assume caller is an object with a __call__ method
        name = caller.__class__.__name__.lower()
        doc = caller.__call__.__doc__
    evaldict = dict(_call_=caller, _decorate_=decorate)
    return FunctionMaker.create(
        "%s(func)" % name,
        "return _decorate_(func, _call_)",
        evaldict,
        doc=doc,
        module=caller.__module__,
        __wrapped__=caller,
    )


# ####################### contextmanager ####################### #

try:  # Python >= 3.2
    from contextlib import _GeneratorContextManager  # type: ignore
except ImportError:  # Python >= 2.5
    from contextlib import GeneratorContextManager as _GeneratorContextManager


class ContextManager(_GeneratorContextManager):
    def __call__(self, func):
        """Context manager decorator"""
        return FunctionMaker.create(
            func, "with _self_: return _func_(%(shortsignature)s)", dict(_self_=self, _func_=func), __wrapped__=func
        )


init = getfullargspec(_GeneratorContextManager.__init__)
n_args = len(init.args)
if n_args == 2 and not init.varargs:  # (self, genobj) Python 2.7

    def __init__(self, g, *a, **k):
        return _GeneratorContextManager.__init__(self, g(*a, **k))

    ContextManager.__init__ = __init__  # type: ignore
elif n_args == 2 and init.varargs:  # (self, gen, *a, **k) Python 3.4
    pass
elif n_args == 4:  # (self, gen, args, kwds) Python 3.5

    def __init__(self, g, *a, **k):
        return _GeneratorContextManager.__init__(self, g, a, k)

    ContextManager.__init__ = __init__  # type: ignore

contextmanager = decorator(ContextManager)


# ############################ dispatch_on ############################ #


def append(a, vancestors):
    """
    Append ``a`` to the list of the virtual ancestors, unless it is already
    included.
    """
    add = True
    for j, va in enumerate(vancestors):
        if issubclass(va, a):
            add = False
            break
        if issubclass(a, va):
            vancestors[j] = a
            add = False
    if add:
        vancestors.append(a)


# inspired from simplegeneric by P.J. Eby and functools.singledispatch
def dispatch_on(*dispatch_args):
    """
    Factory of decorators turning a function into a generic function
    dispatching on the given arguments.
    """
    assert dispatch_args, "No dispatch args passed"
    dispatch_str = "(%s,)" % ", ".join(dispatch_args)

    def check(arguments, wrong=operator.ne, msg=""):
        """Make sure one passes the expected number of arguments"""
        if wrong(len(arguments), len(dispatch_args)):
            raise TypeError("Expected %d arguments, got %d%s" % (len(dispatch_args), len(arguments), msg))

    def gen_func_dec(func):
        """Decorator turning a function into a generic function"""

        # first check the dispatch arguments
        argset = set(getfullargspec(func).args)
        if not set(dispatch_args) <= argset:
            raise NameError("Unknown dispatch arguments %s" % dispatch_str)

        typemap = {}

        def vancestors(*types):
            """
            Get a list of sets of virtual ancestors for the given types
            """
            check(types)
            ras = [[] for _ in range(len(dispatch_args))]
            for types_ in typemap:
                for t, type_, ra in zip(types, types_, ras):
                    if issubclass(t, type_) and type_ not in t.__mro__:
                        append(type_, ra)
            return [set(ra) for ra in ras]

        def ancestors(*types):
            """
            Get a list of virtual MROs, one for each type
            """
            check(types)
            lists = []
            for t, vas in zip(types, vancestors(*types)):
                n_vas = len(vas)
                if n_vas > 1:
                    raise RuntimeError("Ambiguous dispatch for %s: %s" % (t, vas))
                elif n_vas == 1:
                    va, = vas
                    mro = type("t", (t, va), {}).__mro__[1:]
                else:
                    mro = t.__mro__
                lists.append(mro[:-1])  # discard t and object
            return lists

        def register(*types):
            """
            Decorator to register an implementation for the given types
            """
            check(types)

            def dec(f):
                check(getfullargspec(f).args, operator.lt, " in " + f.__name__)
                typemap[types] = f
                return f

            return dec

        def dispatch_info(*types):
            """
            An utility to introspect the dispatch algorithm
            """
            check(types)
            lst = []
            for anc in itertools.product(*ancestors(*types)):
                lst.append(tuple(a.__name__ for a in anc))
            return lst

        def _dispatch(dispatch_args, *args, **kw):
            types = tuple(type(arg) for arg in dispatch_args)
            try:  # fast path
                f = typemap[types]
            except KeyError:
                pass
            else:
                return f(*args, **kw)
            combinations = itertools.product(*ancestors(*types))
            next(combinations)  # the first one has been already tried
            for types_ in combinations:
                f = typemap.get(types_)
                if f is not None:
                    return f(*args, **kw)

            # else call the default implementation
            return func(*args, **kw)

        return FunctionMaker.create(
            func,
            "return _f_(%s, %%(shortsignature)s)" % dispatch_str,
            dict(_f_=_dispatch),
            register=register,
            default=func,
            typemap=typemap,
            vancestors=vancestors,
            ancestors=ancestors,
            dispatch_info=dispatch_info,
            __wrapped__=func,
        )

    gen_func_dec.__name__ = "dispatch_on" + dispatch_str
    return gen_func_dec
